Add bedrock endpoints to gov cloud partition

[jasonlatta]

Discovered that bedrock service was not included in the aws-us-gov partition of endpoint.exs when we got the error bedrock-runtime not found in partition aws-us-gov.

To resolve, copied the bedrock service definitions from the AWS Standard partition, replacing the standard region endpoints with gov ones. Also copied over the fips version of endpoints from the gov cloud dynamodb service definition, updating hostname to match the services to avoid this issue in the future if someone tries to use fips versions of he bedrock services.

Steps taken to verify PR:

• Tested usage of the bedrock-runtime in us-gov-west-1 through successful usage of the converse stream api. Operation:

%ExAws.Operation.JSON{
        data: body,
        headers: @json_request_headers,
        http_method: :post,
        path: "/model/#{model_id}/converse-stream",
        service: :"bedrock-runtime"
      }

• Ran mix format
• Ran mix dializer

- Ran `mix test`

[bernardd]

Thanks @jasonlatta!